1. Technical Field
The present invention relates to a method and structure for electric power management that economically satisfies peak power demand and is able to immediately satisfy a sudden substantial increase in power demand.
2. Related Art
A power management system having an energy source may be used to supply electrical power to a facility such as a residence, a factory, a shopping center, etc. Power demand by such a facility may vary greatly with time. For example, the power demand may be very high for short periods of time, and relatively low for long periods of time. The peak power load can be several times an average power load. The energy source must be capable of satisfying the peak power demand. The fabrication costs and maintenance costs of the power management system generally increase as the system""s rated peak power increases.
Additionally, some energy sources are unable to immediately satisfy a sudden substantial increase in power demand. For example, a fuel cell requires hydrogen gas for generating power. Thus a sudden increase in power demand requires a corresponding increase in available hydrogen gas. Since it is often not possible to generate hydrogen gas sufficiently rapidly to keep up with the sudden substantial increase in demand, the fuel cell voltages may fall below acceptable limits and consequently suffer damage.
There is a need for an economical method and structure for satisfying peak power demand, and also for accommodating a sudden substantial increase in power demand.
The present invention provides a power management system for supplying electric power to a load, comprising:
a first electrical circuit element that includes a first direct current (DC) energy source in series with a first rectifier that prevents current backflow into the first energy source; and
a second electrical circuit element that includes a second DC energy source in series with a second rectifier that prevents current backflow into the second energy source, wherein the second electrical circuit element is in parallel with the first electrical circuit element, and wherein an open circuit voltage V10 of the first energy source exceeds an open circuit voltage V20 of the second energy source.
The present invention provides a method for supplying electric power to a load, comprising:
forming a first electrical circuit element that includes a first direct current (DC) energy source in series with a first rectifier that prevents current backflow into the first energy source; and
forming a second electrical circuit element that includes a second DC energy source in series with a second rectifier that prevents current backflow into the second energy source, wherein the second electrical circuit element is in parallel with the first electrical circuit element, and wherein an open circuit voltage V10 of the first energy source exceeds an open circuit voltage V20 of the second energy source.
The present invention provides an economical method and structure for satisfying peak power demand, and also for accommodating a sudden substantial increase in power demand.